Query the number of built-in system notifications by calling the QueryUnreadCount method.

** Sample code:**

cppvoid OnQuerySysmsgUnreadCb(nim::NIMResCode res_code, int unread_count)
{
	if (res_code == 200)
		···
}

void foo()
{
	nim::SystemMsg::QueryUnreadCount(&OnQuerySysmsgUnreadCb);
}

Query the number of built-in system notifications by calling the nim_sysmsg_query_unread_count method.

** Sample code:**

cvoid CallbackNotifySysmsgRes(int res_code, int unread_count, const char *json_extension, const void *callback)
{
	
}

typedef void(*nim_sysmsg_query_unread_count)(const char *json_extension, nim_sysmsg_res_cb_func cb, const void *user_data);
void foo()
{
	nim_sysmsg_query_unread_count func = (nim_sysmsg_query_unread_count) GetProcAddress(hInst, "nim_sysmsg_query_unread_count");
	func("", &CallbackNotifySysmsgRes, nullptr);
}

Mark all built-in system notifications read by calling the ReadAllAsync method. The unread count of the built-in system notifications is reset to 0.

** Sample code:**

cppvoid SysMsgReadAllCb(nim::NIMResCode code, int unread)
{

}
void foo()
{
	nim::SystemMsg::ReadAllAsync(&SysMsgReadAllCb);
}

Mark all built-in system notifications read by calling the nim_sysmsg_read_all_async method. The unread count of the built-in system notifications is reset to 0.

** Sample code:**

cvoid CallbackNotifySysmsgRes(int res_code, int unread_count, const char *json_extension, const void *callback)
{
	
}

typedef void(*nim_sysmsg_read_all_async)(const char *json_extension, nim_sysmsg_res_cb_func cb, const void* user_data);
void foo()
{
	nim_sysmsg_read_all_async func = (nim_sysmsg_read_all_async) GetProcAddress(hInst, "nim_sysmsg_read_all_async");
	func("", &CallbackNotifySysmsgRes, nullptr);
}